Production of hydrogen



A R GRIGGS PP KODUCTION OF HYDROGEN Filed June 12 1920 Aug. 28, 1923.

Aug: 28, W23.

A. R. GRlGGs PRODUCTION OF HYDROGEN Filed June 12, 1920 2 Sheets-Sheet 2 Patented Aug. 28, 1923.

UNITED STATES ARTHUR ROBERT GRIGGS, OF BROMLEY, ENGLAND.

PRODUCTION OF HYDROGEN.

Application filed June 12, 1920. Serial No. 388,660.

T 0 all whom it may concern.

Be it known that I, ARTHUR ROBERT Games, a subject of the Kin of Great Britain and Ireland, residing at iromley, in the county of Kent, England, have invented Improvements in and Relating to the Production of Hydrogen, of which the following is a specification.

This invention relates to improvements in and relating to the production of hydrogen by thealternatereduc-tion and oxidation of heated iron or iron ores by means of reducing gases and steam respectively.

It has been proposed to carry out the pro cess in indirectly or externally heated retorts in which the iron reaction mass is contained. The retorts situated in a suitable furnace, are externally heated by burning the gases from the reduction phase which still contain a considerable proportion of combustible gas. Retorts of small cross section must be used for the rapid transmission of the heat, and for the production of relatively large amounts of hydrogen,

' furnaces having as many as thirty to forty retorts are required, with the consequent large number of gas and steam connections, each individual retort requiring connections both at the top and bottom. This, besides leading to a complicated plant, restricts the capacity of a unit by reason of the number of retorts that can be satisfactorily heated in a single furnace.

To overcome the objections to this type of hydrogen plant it has been proposed to employ generators in which the reaction mass is heated both externally or indirectly and internally or directly so that large quantities of reaction material can be employed in a single unit. In all such cases, however, both the direct and the indirect heating by combustion are intermittent, that is, they cease during'th'e oxidation phase of the reaction mass, except when the indirect heating is obtained by means of a separately fired producer or the like.

It has also been proposed to employ a large chamber or decomposer to contain the reaction mass Which is internally or directly heated by complete or partial combustion of the reducing gas with air, the low calorific power exhaust gas being employed to heat a boiler or being burnt in a space around the chamber or decomposer, but in the latter method of utilizing the e.\'

haust gas the chamber or decomposer has been incapable of being cut off from communication with the space around it. Iturthermore it has been proposed to combine two or more such chambers or decomposers and to employ the gases from the reduction phase of one or several of them for internally heating another or others,

but in such cases there has been no provision made for external or indirect heating by means of gases from the reduction phase.

Now the present invention relates to the production of hydrogen by the iron reaction process as aforesaidbut in a combination of .closed retorts, chambers or decomposers enclosed in a suitable furnace, the object being to render it possible to utilize retorts or chambers of relatively large cross section. and at the same time heat the re action mass more .evenly throughout and to maintain the necessary heat by internal combustion, at suitable intervals, of gases resulting from the reduction phase that is, gases resulting from the passing of reducing gas through reaction material, or gases resulting from the passing of these resultant gases (alone or with admixture of additional reducing gas) through further reaction material for purposes of reduction, or mixtures of gases so resultingand by continuous combustion external to the iron-containing retorts or chambers of gases resultiug from the reduction phase or of the products of partial combustion of such gases after use for internal heating or for simultaneous internal heating and initial reduction, or of mixtures of such gases and such products of partial combustion.

Owing to the continuous external combustion, there is no cessation of external heat ing during the oxidation or internal heating phases. As gases resulting from the reduction phase are only available intermittently from a given retort or chamber, it follows that two or more retorts or chambers, or groups of retorts or chambers, must be employed so that at least one retort or chamber, or group, may always be on the reducing phase and supplying gases for the periodic. internal and continuous external heating by combustion. Therefore, to maintain'the desired heating, in apparatus consisting of a combination of two groups of retorts or chambers this continuous supply of gases resulting from the reduction phase in one group or the other is at some times burnt outside the retorts or chambers and at other times partially burnt inside a retort or chamber or group, are selectively utilized by leading them, that is, the said gases from a group during the earlier part of the reduction phase, when their calorific value is still low and when the other group is on the hydrogen making phase, are led directly into the furnace and there burning them to maintain the external heating, while during the latter part of the reduction phase, when their calorific value is higher, these gases are led (after removal of the bulk of the water vapor formed during reduction) into the other group for the purpose of internal heating, the resulting products passing into the furnace where the remaining combustible gases are burnt outside the retorts or chambers, thus maintaining the continuity of external heating. Obviously a portion of the gases resulting from the reduction phase may be burnt outside the retorts or chambers whilst the remainder (with or Without admixture of additional reducing gas) is being completely or partially burnt internally.

The said gases from the latter period, stage or part of a reduction phase in one group, when their calorific value is higher, may also be used to effect an initial reduction in the other group, either simultaneously with the said internal heating by restriction of the supply of air for combustion, or immediately following the internal heating. in both cases additional reducing gas may be admitted with the said gases for the purpose of supplementing the supply. This selection and utilization of gases resulting from later periods, stages or parts of the reduction phase for further purposes of reduction effect an economy in the total consumption of reducing gas. I

It is evident from the above description of the method of working that in apparatus consisting of two groups of retorts or chambers reduction of the reaction material in each group may be divided into two distinct periods, stages or parts, the first or initial period of reduction in one group being effected concurrently with or immediately following the internal heating by gases resulting from the later period of reduction in the other group, and the later or final period of reduction being effected by the passage of reducing gas alone through the reaction material.

In apparatus consisting of more than two groups of retorts or chambers after any such initial reduction during internal heating, further reduction may be effected by gases resulting from a later period of reduction of reaction material in another or other groups, such further reduction constituting an intermediate period or stage of reduction which is followed by the final period of reduction effected with reducing gas alone, it being found necessary to finish the reduction with practically fresh reducing gas.

\Vhenevcr gases resulting from reduction of the reaction material are used for further purposes of reduction the bulk of the water vapor formed during the previous reduction is removed by suitable means. Additional reducing gas may also be admitted with the said gases for the purposes of supplen'ienting the supply.

In more particularly describing the invention, the apparatus chosen for illustration is characterized by the arrangement and connection of the retorts or chambers in two units or groups in such wise that they may be continuously heated externally by combustion of gases resulting from the reduction phase or of the products of their partial combustion issuing from either one of the said units or groups supplemented at suitable intervals by internal heating of the units or groups alternately. The external or indirect heating contributes to the greater extent in maintaining the temperature of the reaction mass but it is supplemented by internal or direct heating at suitable intervals characterized by the use at this stage of gases resulting from the reduction phase or" either unit or group for the heating of the other, from which gases, the bulk of the water vapor formed during reduction of the reaction mass may be removed before combustion by a suitable pipe condenser or other means fitted t0 the connecting pipe between the two units or groups.

For the purpose of obtaining a conduction surface as large as possible for transmitting the maximum amount of heat from the furnace to the reaction massthe retorts or chambers may be of rectangular cross section; but any shape giving a large perimeter in proportion to its area may be employed.

By a suitable arrangement of pipe connections and valves, gases resulting from the reduction phase of either unit or group of retorts or chambers can be led into the furnace enclosing both units or groups and there burnt with a. regulated supply of air. By the said arrangement also gases from the latter part of the reduction phase of either unit or group can be led into the other and there partially burnt with air for direct heating (with or without an initial reduction) of the reaction mass, the hot products escaping from the other end of the retorts or chambers being led into the furnace Where the remaining combustible gas is burnt. By the said use of gases resulting from the reduction phase of either unit or group at a suitable stage in the reduction for the internal heating of the other, it is possible to avoid overheating and fusing of the reaction each group, for instance, as is indicated by the dotted lines at the lower part of Fig. 2,

there may be an additional retort or chamber in each group. The two grou'ps of re-' torts or chambers marked 30 and 40 respectively are contained in and heated by a refractory lined furnace 1 enclosed in a metal shell 2 and provided with connections 11, 12 and 21 at the bottom for the supply of gas and air. The products of combustion are collected in a flue 3 constructed round the top of the furnace by means of suitable ports and are discharged by two vertical uptakes or flues 5 controlled by dampers 6 into the air.

A reducing gas supply pipe 7 is connected with either group 30, 40, by the three-way valve 8. The reducing gas passes down through the reaction mass in one group and the gases resulting from the reduction phase leave the bottoms of the retorts or chambers by the pipe 9 communicating with the fourway valve 10, thence either to the furnace by the way of the burner main 11, and burner pipes 12, or to the second group for internal heating by the way of the vertical pipe 13 to the connection 14, leading into the tops of the retorts or chambers. If the valve 15 be open as shown these gases pass into the right hand group 40.

The vertical pipe 13 which is connected to the lower branch 10 of the body of the valve 10, is provided with an arrangement for removing the water vapor formed during reduction in the first group such as a water jacket 16 through which water is circulated, or other suitable and efficient means. The spent reducing gas, that is to say, the gases resulting from the reduction phase, on being admitted to the tops of the second group 40 of retorts or chambers by the valve 15, meet a regulated supply of air, which may be preheated if necessary, admitted by the valve 17 into the heads of the retorts or chambers. The upper portions of the retorts or chambers themselves are formed into and used as combustion chambers and provided with fireproof linings 18.

The products of combustion and unburnt gases, passing downwards through the reac-.

tion mass, heat the same in their course and may be caused by suitably restricting the air supply to effect an initial reduction. The products and gases then pass out of the .unburnt gases escaping into the furnace at this stage are burnt with a limited supply of air which can be regulated by the valve 22. The products of combustion pass upwards through the furnace, heating the retorts or chambers during their passage, and escape to the atmosphere through the ports 4'and flue 3 and chimney stacks 5, 5, which are provided with controlling dampers 6, 6.

When the reduction of the reaction mass in one group of retorts or chambers is complete, theair valve 17 is closed and the control valve 8 reversed, thereby turning the supply of reducing gas over to the other group. At the same time the steam purging supply is turned on by the valve 23, the gases remaining in the retorts or chambers and the impure hydrogen generated being dri en against the pressure of the reducing gas into the other group by the way of the pipe 9, control valve 10, and vertical pipe 13.

When purging is complete the valves 23 and 15 are shut.

The hydrogen prdoucing steam supply 24 is then turned on and at the same time the hydrogen outlet valve 25 is opened which may communicate to a washer seal box.

During hydrogen making or oxidation cf the mass in one group of retorts or chambers, reduction is proceeding in the other and the spent reducing gas (the gases resulting from the reduction phase) passed into the furnace by the way of pipe 19,- control valve 10, and furnace burner main 11. At the-completion of the oxidation stage, the steam supply 24 is shut off and the hydrogen outlet 25 closed. The valve 26 is then opened and the control valve 10 reversed so that the spent reducing gas (the gases re sulting from the reduction phase) from the right hand group now passes up the vertical pipe 13, the bulk of the water vapor being removed, through the valve 26 into the left hand group which has just finished oxidation.

The air supply 27 is opened and the internal heating stage commences the products of combustion and residual combustible gases leaving the lower ends of the retorts or chambers by the pipes 9, through the control valve 10, which has been reversed and thence into the burner main 11 to the furnace burner 12. At the end of the heating stage in the left hand group the right hand group is put on hydrogen making and the &

left hand group on reduction proper as in the preceding case.

In this way an internal heating stage immediately follows after oxidation and precedes the reduction proper, the cycle taking place in the two groups of retorts .or chambers separately.

The top control valves and hydrogen outlets 25 and 28 are shown in Fig. 2, for convenience at the side of the apparatus but any other suitable position may be adopted.

lhe methods of working hereinbefore described are obviously only examples, and appa ratus constructed for carrying out this invention. whether consisting of two or more groups of retorts or chambers, can be modified in a number of ways both for car- -r \ing out the alternative methods of working and for the purpose of obtaining any desired capacity in a convenientmanner.

What I claim is 1. A process for the production of hydrogen by the alternate oxidation and reduction of iron reaction material contained in chambers or retorts wherein gases resulting from the reduction phase are utilized in directly heating the reaction material by internal combustion at intervals and in continuously heating it by external combustion.

2. A process for the production of hydro gen by the alternate oxidation and reduc tion of iron reaction materialcontained in chambers or retorts wherein gases resulting from the reduction phase are utilized in directly heating the reaction material by internal combustion at intervals and in continuously heating it by external combustion, the gases from the reduction phase being selected for combustion entirely outside the chambers or retorts and for partial combustion inside the chambers or retorts followed by more complete combustion outside them.

3. A process for the production of hydrogen by the alternate oxidation and reduction of iron reaction material contained in chambers or retorts wherein the reduction phase is divided into periods, an initial reduction in one chamber or retort is effected with gases derived from another chamber on a later period of the reduction phase, water vapor is removed from said gases prior to their use for effecting said initial reduction and gases from the reduction phase are utilized in heating the reaction material.

4. A process for the production of hydrogen by the alternate oxidation and reduction of iron reaction material contained in chambers or retorts wherein the reduction phase is divided into periods, an initial reduction in one chamber or retort and an intermediate reduction in another are efi'ected with gases derived from other chambers on later periods of the reduction phase, water vapor is removed from Said gases prior to their use for efi'ecting said initial and intermediate reduction, and gases from the reduction phase are utilized in heating the reaction material.

5. A process for the production of hydrogen by the alternate oxidation and reduction of iron reaction material contained in chambers or retorts wherein the reduction phase is divided into periods, an initial reduction and internal heating in one chamber or retort are effected with gases derived from another on a later period of the reduction phase, water vapor is removed from said gases prior to their use for said initial reduction and internal heating, and gases derived from the reduction phase are utilized in continuously heating the reaction material by external combustion.

6. The process specified in claim 5 wherein the initial reduction and internal heating stage are combined, substantially as described.

7. Apparatus for the production of hydrogen comprising a plurality of separate chambers or retorts containing iron reaction material, a combustion space around said chambers or retorts, means for admitting reducing gas, air, and steam to each of said chambers or retorts, means for connecting any two of the several chambers or retorts to each other and for leading gas from them to the combustion space outside them, means for controlling the admission of reducing gas, air and steam for closing the said connections, outlet means for taking off the hydrogen, and means for controlling same;

8. Apparatus for the production of hydrogen comprising a plurality of chambers or retorts containing iron reaction material, a combustion chamber enclosing said chambers or retorts, means for admitting reducing gas, air, and steam to each of said chambers or retorts, means for conducting gases resulting from reduction in one chamber or retort into any other chamber or retort, means for conducting gases from each retort to the enclosing chamber for combustion therein, means for controlling the admission of reducing gas, air, and steam and for closing the said connections and a controlled outlet for taking off the hydrogen.

9. Apparatus for the production of hydrogen comprising a. plurality of chambers or retorts containing iron reaction material, a combustion chamber enclosing said chambers or retorts, means for admitting reducing gas, air, and steam to each of said chambers or retorts, means for conducting gases resulting from reduction in one chamber or retort into any other chamber or retort, external conduits connecting each chamber or retort with said enclosing combustion chamber, valves controlling the admission of reducing gas, air, and steam and valves controlling said external conduits,

and a controlled outlet for taking 011' the hydrogen, the arrangement being such that heating of the retorts or chambers by external combustion may continue without interruption while oxidation is taking place in a chamber or retort.

10. Apparatus for the production of hydrogen comprising a plurality of chambers or retorts containing iron reaction material, a combustion chamber enclosing said chambers or retorts, means for admitting reducing gas, air, and steam to each of said chambers or retorts, means for conducting gases resulting from reduction in one chamber or retort into any other chamber or retort, means for removing the bulk of the water vapor from said gases before passing them into said other chamber or retort, external conduits connecting each chamber or retort with said enclosing combustion chamber, valves controlling the admission of re ducing gas, "air, and steam and valves controlling said external conduits, and a controlled outlet for taking off the hydrogen. the arrangement being such that heating of the retorts or chambers by external co1nbustion may continue without interruption while oxidation is taking place in a chamber or retort.

11. Apparatus for the production of hy drogen comprising a plurality of chambers or retorts, each formed with a combustion space in its head and containing, below said space. iron reaction material, a combustion chamber enclosing said chambers or retorts, means for admitting reducing gas, air and steam to each of said chambers or retorts, means for conducting gases resulting from reduction in one chamber or retort into any other chamber or re'tort, means for conducting gases from each retort to the enclosing chamber for combustion therein and means for controlling the admission of reducing gas, air, and steam and for closing the said connections. and a controlled outlet for taking off the hydrogen.

1.2. Apparatus for the production of hydrogcn comprising a plurality of groups of chambers or retorts containing iron reaction material, means for admitting reducing gas, air, and steamvto the several chambers or retorts of each group, means for effecting combustion of gas external to said chambers or retorts, means for connecting the groups of chambers or retorts to each other and for leading gas from them to the means for effecting combustion, and means for controlling the admission of gas. air, and steam and for closing the connections between the groups of chambers or retorts, the chambers or retorts of each group being adapted to be ope ated as one, an outlet for taking off the hydrogen from each group and means for controlling each of said outlets.

13. A. process for the production of hydrogen by the alternate oxidation and reduction of iron reaction material contained in chambers or retorts wherein the reduc tion phase is divided into periods, an initial reduction in one chamber or retort is cft'ected with gases derived from another on a, later period of the reduction phase supplemented by additional reducing gas. water vapor is removed from said gases from the reduction phase prior to their use for effecting said initial reduction, and gases from the reduction phase are utilized in heating the reaction material.

it. A process for the production of hydrogen by the alternate oxidation and reduction ot iron reaction material contained in'chambers or retorts wherein the reduction phase is divided into periods, an initial reduction in one chamber or retort and an intern'iediate reduction in another are effected with gases derived from other chambers on later periods of the reduction phase, water vapor is removed from said gases prior to their use for effecting said initial and intermediate reduction. said gases are supplemented by additional reducing gas, and gases from the reduction phase are utilized in heating the reaction material.

Signed at London, England, this 27th day of May, 1920.

ARTHUR ROBERT GRIGGS. 

